The invention relates to a tool handling device for a machine tool comprising a plurality of stationarily arranged tool holders and a tool gripper arrangement for shifting tools between a transfer station and the tool holders.
Such a tool handling device is for example disclosed in the German patent publication 10,020,801 A. In the case of this known device for handling or shifting tools three degrees of freedom are necessary with the result that the moving mechanism for the tool gripper arrangement is complex and expensive. Furthermore, long transfer paths and accordingly a relatively slow tool changing operation must be tolerated. In fact, the known device a requires much space and occupies a large floor area.
Furthermore there are so-called drum magazine and chain tool changers, in the case of which for the transfer of the desired tool all tools present in the magazine together with the tool holders have to be moved. Owing to the extremely large mass of the overall arrangement only relatively slow movement is possible and furthermore the drive technology is complex.
One object of the invention is to create a tool handling device which in comparison with known devices renders possible a simpler system of movements with only two degrees of freedom, shorter displacements and a consequently a more rapid tool changing operation.
One advantage of the tool handling device of the invention is more particularly that the entire tool changing operation may be performed with two NC axes, namely by the combination of a translatory and a rotary movement, by virtue of which the movement into position to each tool holder and, respectively, each tool may take place at a high speed. Owing to the stationary storage of the tools handling may be performed extremely dynamically.
Owing to the arrangement of the tools in an annular form a high degree of compactness is made possible, since owing to the geometry more tools can be stored on a circular arc as compared with other configurations. Moreover, very constant change times may be realized.
The tool handling device in accordance with the invention may be employed both as a tool magazine and also a tool magazine extension module for a tool magazine of a machine tool. In this case there is both a space saving integration in the machine tool and, respectively, in the machining center and also an arrangement juxtaposed to the machine tool, more particularly in the case of employment as a gripper. Owing to the use as a magazine extension module the product spectrum of a single machine may be substantially extended. There is the possibility, for example, owing to the large capacity, of accepting sister tools, that is to say tools having the same references as the main tool, when the main tool is made unavailable by the control owing to fracture of the main tool or owing to monitoring its time in service.
The plane of motion of the tool gripper arrangement may with advantage be made parallel to the plane of the tool holders, the held portion (in each case directed toward this plane of motion) of the tools held in the tool holders assuming a position between their gripping jaws given a suitable positioning of the tool gripper arrangement. This means that a movement in parallelism to the pivot axis of the boom is unnecessary.
The tool gripper arrangement is, in its unloaded open position, best designed for running over and to tools held in the tool holders. This shortens the displacements and radially adjacent tools may be very rapidly reached. This advantage is even more significant, if at least some of the tool holders are designed to be flush in the radial direction, since then radial displacement and moving over and to tool holders is made possible by the tool gripper arrangement without additional pivotal motion.
In accordance with a preferred design the tool holders are arranged in at least one row and more particularly in concentric rings about the pivot axis. This arrangement means that a high degree of compactness is achieved, since owing to the arrangement on a single circular arc more tools may be stored than in other geometrical arrangements. Furthermore, very regular change time may be achieved. Obviously in principle other row arrangements are possible, as for example linear, polygonal, oval or other arrangements. In the case of every arrangement, with the exception of a concentric annular arrangement, on moving to the tool holders a pivotal and a translatory movement of the boom must be performed simultaneously.
In order to be able to perform radial shifting of the loaded tool gripper arrangement preferably at least one radial shifting lane is left free.
More particularly, holding rings are suitable for an annular arrangement, inner holding rings being preferably provided with tool holders on either side.
In or adjacent to the external holding ring a more particularly manual loading and unloading station is provided which is conveniently so designed that in its portion on the side, facing radially outward, of the outer holding ring a plurality of tool holders and preferably a shifting lane are arranged, such shifting lane extending through at least holding ring. This means that such outer tool holders may be manually loaded with tools or tools, which are no longer to be utilized, may be removed, the associated shifting lane permitting rapid movements and short displacements of the tool gripper arrangement.
The radial distance apart of the holding rings is conveniently of such a size that a pivotal movement of the loaded tool gripper arrangement therebetween is possible.
In accordance with an expedient design the boom is able to be changed in length in a telescopic manner. Alternatively, the tool gripper arrangement could also be arranged in a sliding fashion on a rigid boom.
The gripping movement of the gripping jaws of the tool gripper arrangement and/or the radial movement of the tool gripper arrangement is preferably performed pneumatically, hydraulic cylindrically or electrically using suitable actuators, as for example servo motors or servo cylinders.
In order to render possible operations involving endless rotary movements of the boom it is an advantage to provide a slip ring arrangement for the transmission of electrical signals and/or electrical power to the boom.
In a simple design the tool gripper arrangement has a pair of gripping jaws, it also being possible to provide two pairs of gripping jaws (as double grippers) in order to render possible an even faster tool change. The deposit of the blunted or spent tool and the making available of a fresh tool can take place in parallelism to the principal time.
Further advantageous developments and convenient forms of the invention will be understood from the following detailed descriptive disclosure of one embodiment thereof in conjunction with the accompanying drawings.